1. CLASSIFYING CHEMICAL REACTIONS
Review of Science 10 (Section 2.5) Pg

2. Science 10 Review:
When counting elements, don’t forget to look at both the subscript and the coefficient.
For example:
P2O5 = has 2 phosphorus atoms and 5 oxygen atoms
2P2O5 = has 4 phosphorus atoms and 10 oxygen atoms
Because there are 2 molecules (indicated by the coefficient) and 2 atoms in each molecule (indicated by the subscript) –
So you multiply!!

3. Remember: 2O2(g) + 4H2(g)  4H2O(l)
Never change a subscript to balance an equation!
O2(g) + H2(g)  H2O(l) Is unbalanced – but you can’t change it the following way!
O2(g) + H2(g)  H2O2(l) X
Make sure the coefficients are the lowest whole-number ratio :
2O2(g) + 4H2(g)  4H2O(l)
This is a balanced formula but these are not the lowest numbers you could use:
O2(g) + 2H2(g)  2H2O(l)

4. Balancing Chemical Equations
1) Write the chemical formulas for the reactants and products including the states
Cu(s) + AgNO3(aq)  Ag(s) + Cu(NO3)2(aq)
Balance the element (atom or ion) present in the greatest number by multiplying by the lowest coefficient possible
(NO3)2(aq) = 2 present (lowest coefficient possible to balance = 2)
Cu(s) AgNO3(aq)  Ag(s) + Cu(NO3)2(aq)
3) Repeat step 2 for the rest of the elements
Now we have 2 Ag, so balance the other side
Cu(s) + 2AgNO3(aq)  2Ag(s) + Cu(NO3)2(aq)
4) Count elements on each side of the final equation to ensure they balance:
1 Cu(s) = 1 Cu(s) ; 2Ag = 2Ag(s) ; 2 NO3 = (NO3)2(aq)

5. What do you remember? Composition (Formation) Decomposition Combustion
In Science 10 you learned about five reaction types, can you match them up
Composition (Formation)
Decomposition
Combustion
Single Replacement
Double Replacement
CH4(g) + O2(g)  CO2(g) + H2O(g)
Mg(s) + O2(g)  MgO(s)
Cu(s) + AgNO3(aq)  Ag(s) + Cu(NO3)2(g)
CaCl2(aq) + Na2CO3(aq)  CaCO3(s) + NaCl(aq)
H2O(l)  O2(g) + H2(g)

6. Classifying Chemical Reactions: Composition (Formation)
2Mg(s) + O2(g)  2MgO(s)
element + element  compound
Predict and balance the following:
Li(s) + Cl2(g) 
Na(s) + F2(g) 
Ba(s) + N2(g) 

7. Classifying Chemical Reactions: Decomposition
2H2O(l)  O2(g) + 2H2(g)
compound  element + element
Predict and balance the following:
NaCl(s) 
Sr3P2(s) 
Cs2O(s) 

8. Classifying Chemical Reactions: Combustion
CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)
fuel + oxygen  carbon dioxide + water
Predict and balance the following:
C3H8(g) + O2(g) 
C2H6(g) + O2(g) 
C4H10(g) + O2(g) 

9. Classifying Chemical Reactions: Single Replacement
2AgNO3(aq) + Cu(s)  Cu(NO3)2(aq) + 2Ag(s)
compound + element  compound + element
2NaI(aq) + Cl2 (g)  I2 (s) + 2NaCl(aq)
Predict and balance the following:
NaBr(aq) + O2(g) 
CuCl2(aq) + Al(s) 
Li2CO3(aq) + K(s) 

10. Classifying Chemical Reactions: Double Replacement
2AgNO3(aq) + CuCl2(aq)  Cu(NO3)2(aq) + 2AgCl(aq)
compound + compound  compound + compound
CaCI2(aq) + Na2CO3 (aq)  2NaCl (aq) + CaCO3(s)
Predict and balance the following:
NaBr(aq) + MgO(aq) 
CuCl2(aq) + AlF3(aq) 
Li2CO3(aq) + K2O(aq) 

11. Chemical Puzzler

12. Using the solubility table: